This study tests the hypothesis that amphetamine induced dopamine release is exaggerated in patients with Tourette Syndrome as compared to normal controls. This is based in part on the dopamine hypothesis of Tourette Syndrome which in turn is based upon both postmortem studies showing dopaminergic abnormalities as well as the well known success of dopamine receptor antagonists in the treatment of Tourette Syndrome. In this study intravenous amphetamine is employed to cause a release of dopamine which is visualized by a displacement of the radiotracer ["C]raclopride during PET imaging studies. The degree of this displacement or the radiotracer between a baseline and an amphetamine challenge PET study is a measure of the intrasynaptic dopamine release. The purpose of this study is to demonstrate this release in Tourette patients compared to controls.